//- 设置根元素fontSize~
(function(doc, win) {
//	var resizeEvent = 'orientationchange' in win ? 'orientationchange':"resize";
	var _root = doc.documentElement,
		callback = function() {
			var clientWidth = _root.clientWidth,
				fontSize = 20;
			if(!clientWidth) return;
			if(clientWidth < 320) {
				fontSize = 20;
			} else {
				fontSize = 20 * (clientWidth / 320);
			}
			_root.style.fontSize = fontSize + 'px';
		};
		
//	win.addEventListener(resizeEvent, callback, false);
	if(doc.readyState === "complete" && doc.body){
		callback();
	}else{
		doc.addEventListener('DOMContentLoaded', callback, false);
	}
})(document, window);